NEW DELHI: Air India's six Boeing 787 Dreamliners would remain grounded till February 17, with further delays expected in the tests being carried out by US and Japanese authorities on the faulty lithium ion batteries used in the aircraft.

In effect this means that the newest aircraft in the airline fleet will remain grounded for a month as it was on January 17 that Air India had grounded its Boeing 787 fleet, after the DGCA issued a directive following an advisory by the US regulator Federal Aviation Administration.

Initially, Air India was expecting that the B-787 aircraft would be grounded for about a week only, airline sources said, adding that the six aircraft would remain grounded till February 17 as further delay in the test results were expected.

The airline was looking at the induction and use of the Dreamliners to turn around its financial fortunes, especially due to its fuel saving capability. The aircraft was generating revenues of Rs two crore a day when it was in service since September last year, the sources said.

The Directorate General of Civil Aviation had on January 17 asked Air India to cease Dreamliner operations with immediate effects till a problem with a battery on board was fixed. The DGCA took the decision to ground the aircraft after it received a global advisory from the FAA which came after two incidents of fire caused by the battery.

The FAA's emergency airworthiness directive (AD) required all operators of the Dreamliners to temporarily cease operations of the aircraft. "Before further flights, operators of US-registered, Boeing 787 aircraft must demonstrate to the Federal Aviation Administration (FAA) that the batteries are safe," it said.

The batteries are currently being tested in the US and Japan, where its manufacturer is based, to find out what exactly caused the incident.

Air India has ordered 27 Boeing 787 aircraft. The six aircraft in the fleet were used to operate flights from Delhi to Bangalore, Chennai and Kolkata apart from operating flights to Dubai, Frankfurt and Paris. The airline is now using other aircraft in its fleet to operate these flights.